Solid-state imaging apparatuses are known to have a structure in which photoelectric conversion units are arranged on a substrate and peripheral circuits and part of pixel circuits are arranged on another substrate, and these substrates are electrically connected to each other.
Japanese Patent Application Laid-Open No. 2006-191081 discusses a backside illumination type solid-state image sensor in which photoelectric conversion units on a first substrate are connected to peripheral circuits on a second substrate through bonding pads provided on the front surfaces of the respective substrates in order to improve the sensitivity of the photoelectric conversion units.
Japanese Patent Application Laid-Open No. 2008-235478 discusses an image sensor including a first substrate having photodetection pixels and through wiring and a second substrate having readout circuits. The readout circuit reads an electrical signal via the through wiring and output the signal as an image signal. In this solid-state image sensor, a rear surface of the first substrate faces the readout circuits on the second substrate and the through wiring is electrically connected to the readout circuits at their terminals.